So I'm gonna use this thread to info dump what I've learned about the disc drive, since:
A. Currently it's all in a group chat that's intended for other stuff.
B. There's almost no information about the disc drive anywhere.
C. No idea where else to do it.
The only components that require 5v are the motor driver and the "IC4002". The motor driver does exactly what it sounds like, drive the motors on the disc drive (it probably also takes in 12v, but I haven't traced that rail out yet). Removing that IC has zero consequences and the disc drive is happy. The same cannot be said about IC4002. I have no idea what this IC is, but it seems to take in 5v and then spit out 1v2 (among other things). Yes, I did just say 1v2. The Main IC on the disc drive runs on two voltages: 3v3 and 1v2.
(Red = 3v3, Purple = 1v2)
Originally I just shorted 3v3 and 1v2. Unfortunately that just caused the Main IC to get super hot and the disc drive wasn't recognized. How could I supply power to that rail...? Well, I still had parts from building Fujiflex', and in that BOM was a 1v2 LDO. On the flex its intended to take in 1v8, but the LDO will happily take in 3v3. Perfect! After removing IC4002 and wiring up the LDO, the disc drive was recognized! I then removed the 5v 0ohm resistor (or the fuse, there aren't any markings for the passives, so I have literally no idea what it is), and it still worked! I had essentially entirely eliminated the 5v requirement for the disc drive by using a simple LDO. I even trimmed the disc drive board for fun, since nothing on that side of the board was needed.
(The disc drive on the bottom in the left picture is where I tried shorting the two rails. Obviously verification would fail, but the disc drive just didn't do anything and resulted in 160-1400)
I also found a nice spot to put the LDO:
Not sure how much power the 1v2 rail draws, but the LDO seems fine for now.
Next thing I tried to remove was the SDRAM. Obviously it didn't work, but the way it didn't work was..interesting. The disc drive was failing verification (error 160-1402). Normally when the drive isn't found the console shows 160-1400, So the main IC was still functional. Probably just means that the AES engine uses some of the SDRAM, but no one knows, the disc drive firmware has yet to be extracted (that's kinda the goal with these scans: find how Nintendo/Panasonic programs these in the factory and somehow use that to dump the firmware).
I then cut off the other side of the board and tried to rewire SATA, and the console doesn't recognize the disc drive. I know SATA is two differential pairs, so I twisted some magwire tight with my dremel and rewired to the traces (honestly i should have just used the CM9/CM10 pads). The disc drive worked just fine with 3v3 and that 1v2 LDO, and it's definitely not bypassing the capacitors. I did this on a WUP-30, which entirely removes those capacitors (and the WUP-50 brought them back? WUP-40 is missing them too). I also tried rewiring some pullups/pulldowns for the lights, and still nothing.. Not sure what the deal here is. I'm sure I'll figure it out eventually, but for now I need to find another 35 drive board to test on.
Also, I noticed that there is a 3rd voltage..I think?
Measuring this with my meter I get 1v6. The weird thing about this voltage is that there are zero components for it besides some capacitors and certain traces have pullup resistors to it. Maybe the Main IC has some internal regulator? I don't think it's very important though, just something random I found.
I've also traced out the RAM, but there's nothing special going on there really.
Everything is sitting on an .xcf on my hard drive. I'll upload it to the google drive once I'm finished with tracing it all.
drive.google.com
